The present invention relates to a false-twist nozzle; or more specifically, it relates to an improved structure of a false-twist nozzle which is applicable as a spinner for producing a so-called fasciated yarn by fluid jet process.
In spinning of such a fasciated yarn, fibers of sliver or roving are drafted by any suitable drafting mechanism and then transferred by fiber supply rollers, such as front rollers in the drafting mechanism, into a false-twist nozzle, where the fibers thus drafted are placed under the influence of aspirating and rotating actions imparted by a flow of jetted fluid whereby they are twisted and then untwisted, while being advanced continuously, to form a spun yarn by binding non-twisted core fibers with the ends of peripheral fibers.
For successful spinning of a yarn in such a process, it is essential for the above-said false-twister to have functions of drawing in and rotating, therefore twisting, the fibers of sliver properly by means of a flow of jetted fluid. To permit accomplishment of such functions, it is required that the false-twist nozzle should have its fluid conduit, through which fluid medium is jetted into a yarn passage in the nozzle, formed therein extending and opened into the yarn passage in an acute angle with respect to the longitudinal central axis thereof and eccentrically or in an offset relation to that central axis so as to impart effective aspirating and twisting actions on the fibers of yarn.
However, because the diameter of such fluid conduit falls usually within the range of less than 1 mm and it must be formed by drilling from the exterior of the nozzle body toward the yarn passage due to its inherent construction, it has been extremely difficult to drill such a small diameter with a desirable degree of accuracy. The difficulty lies in that a drill bit to be used for making a small diameter is very liable to be bent or even broken during drilling operation and that such a drill, if not bent or broken, tends to be deflected or to make a spin-out at its tip end easily in drilling, thus inviting poor accuracy in positioning of opened outlet of the fluid conduit, with a result that fiber twisting action of the false-twist nozzle will be degraded by inaccurate tangential relation of the fluid conduit to the yarn passage. In addition, the blind drilling of the fluid conduit hole being formed by drilling makes it practically impossible to check its opened outlet for being positioned properly, and an error in the outlet position, if any, cannot be remedied. Furthermore, since drilling must be performed from the exterior of the false-twist nozzle body toward the yarn passage formed therein, it is inevitable that the innermost end edge portion of the conduit hole drilled tangentiably to and in communication with the yarn passage will be formed with a harmful burr which may cause damages to the yarn moving past the passage. To make matters worse, it is very difficult to thoroughly deburr the conduit hole because the yarn passage is formed with a relatively small diameter and also the outlet of the drilled fluid conduit hole is positioned deep within the yarn passage. Presence of burr thus formed at the fluid conduit outlet in the yarn passage may seriously affect the twisting effect of the false-twist nozzle because smooth flow of jetted fluid is obstructed by such burr.